The present invention relates to perimeter seals for electromagnetic shielded doors and, more particularly, to a constant force spring perimeter seal for an electromagnetic shielded door.
Existing radio frequency (RF) shielded doors utilize a mechanical contact mechanism that is prone to wear, requires excessive maintenance, and requires a large amount of force to engage and disengage. Existing RF door seal mechanisms rely on a scraping action of a knife edge between two rows of compression spring.
Currently, RF door seal mechanisms encounter a large amount of mechanical resistance to opening and closing the door. As a result, large mechanical handles, levers, cam mechanisms, and elaborate latching schemes are required to overcome this force. In addition, if no externally powered mechanism is present to aid in the opening of the door, the opening of the door relies entirely on the strength of an individual to overcome the compressive force between the spring fingers and the knife edge. There have also been reports of injuries sustained to the wrist, shoulder, and back of operators using this style door. The latching mechanism is also prone to failure which poses a possible safety concern of locking people inside of an RF shielded room.
As can be seen, there is a need for a constant force spring perimeter seal for an electromagnetic shielded door that may include a rolling spring mechanism that may allow the door to open and close easily and smoothly while still achieving the metal to metal seal required for proper RF shielding and may transmit a repulsive force that aids in the opening of the door.